silicon and stannic-oxide

Herein we show the development of biointerfaces on indium-tin oxide (ITO) surfaces prepared from organophosphonate self-assembled monolayers. The interfaces were prepared in a stepwise fabrication procedure containing a base monolayer modified with oligo(ethylene oxide) species to which biological recognition ligands were attached. The density of ligands was controlled by varying the ratio of two oligo(ethylene oxide) species such that only one is compatible with further coupling. The final biointerface on ITO was assessed using cell adhesion studies, which showed that the biointerfaces prepared on ITO performed similarly to equivalent monolayers on gold or silicon.

Topics: Gold; Indium; Organophosphonates; Silicon; Tin Compounds

Tin oxide (SnO2) is considered a very promising material as a high capacity Li-ion battery anode. Its adoption depends on a solid understanding of factors that affect electrochemical behavior and performance such as size and composition. We demonstrate here, that defined dispersions and structures can improve our understanding of Li-ion battery anode material architecture on alloying and co-intercalation processes of Lithium with Sn from SnO2 on Si. Two different types of well-defined hierarchical Sn@SnO2 core-shell nanoparticle (NP) dispersions were prepared by molecular beam epitaxy (MBE) on silicon, composed of either amorphous or polycrystalline SnO2 shells. In2O3 and Sn doped In2O3 (ITO) NP dispersions are also demonstrated from MBE NP growth. Lithium alloying with the reduced form of the NPs and co-insertion into the silicon substrate showed reversible charge storage. Through correlation of electrochemical and structural characteristics of the anodes, we detail the link between the composition, areal and volumetric densities, and the effect of electrochemical alloying of Lithium with Sn@SnO2 and related NPs on their structure and, importantly, their dispersion on the electrode. The dispersion also dictates the degree of co-insertion into the Si current collector, which can act as a buffer. The compositional and structural engineering of SnO2 and related materials using highly defined MBE growth as model system allows a detailed examination of the influence of material dispersion or nanoarchitecture on the electrochemical performance of active electrodes and materials.

Topics: Electric Power Supplies; Indium; Ions; Lithium; Nanoparticles; Silicon; Tin Compounds

Topics: Metals; Nanotubes, Carbon; Oxides; Paper; Semiconductors; Silicon; Temperature; Tin Compounds

Light addressing is an emerging and sophisticated technique that can induce pinpoint and/or patterned neuronal activation in cultured neurons. We previously developed a light-addressable electrode using hydrogenated amorphous silicon (a-Si:H), which was sandwiched between a tin oxide (SnO(2)) substrate and a passivation layer of zinc antimonate (ZnOSb(2)O(5)) dispersed epoxy. This research developed an experimental system that simultaneously implemented light-addressed stimulation and Ca(2+) imaging of neuronal activities. The translucent and thin laminated structure of our electrode permitted optical accesses from two directions: Ca(2+) imaging from above and light addressing from beneath. The submillisecond bright/dark switching property of our electrode offered light-addressed stimulation without causing interference with Ca(2+) imaging. To provide patterned illumination for light addressing, a digital micromirror device was installed in the system as an active photomask. The system could induce pinpoint neuronal activation at a cellular level.

Topics: Action Potentials; Animals; Calcium; Cells, Cultured; Cerebral Cortex; Coculture Techniques; Electric Stimulation; Electrodes; Equipment Design; Light; Microelectrodes; Neuroglia; Neurons; Rats; Rats, Wistar; Silicon; Tin Compounds

A bacteriorhodopsin (bR)-silicon n-channel metal-oxide field-effect transistor (NMOSFET) monolithically integrated photoreceiver is demonstrated. The bR film is selectively formed on an external gate electrode of the transistor by electrophoretic deposition. A modified biasing circuit is incorporated, which helps to match the resistance of the bR film to the input impedance of the NMOSFET and to shift the operating point of the transistor to coincide with the maximum gain. The photoreceiver exhibits a responsivity of 4.7 mA/W.

Topics: Bacteriorhodopsins; Electric Conductivity; Electrophoresis; Halobacterium salinarum; Light; Optics and Photonics; Oxides; Photochemistry; Silicon; Tin Compounds; Transistors, Electronic

We describe the electrical and luminescence properties of nanocrystalline silicon (nc-Si) based red electroluminescent (EL) devices using an indium tin oxide (ITO) and/or gold (Au) films as a surface electrode, and the variation in the transmittance and resistivity of two electrodes with various film thicknesses. The increase in the film thickness from 50 to 200 nm of the ITO electrode led to the lowering of resistivity from 2.0 x 10(-3) to 9.1 x 10(-4) omega cm and almost the same value (83-92%) of transmittance in the red region. On the other hand, the Au electrode was lowered the resistivity from 1.8 x 10(-4) to 1.6 x 10(-5) omega cm and the transmittance in the red region from 42 to 1.8% with increasing the film thickness from 10 to 80 nm. Moreover, the red luminescence from the EL devices using the ITO and/or Au electrodes having thickness of 200 and 10 nm, respectively, obtained by applying the direct current forward voltage above 4.5 and 2.5 V and/or by flowing the forward current density above 53 and 38 mA/cm2, respectively. However, the luminescence intensity of EL device with the ITO electrode strengthened more than about one order of magnitude in comparison to that of the EL device with the Au electrode. This was due to the high value of transmittance in the red region of the ITO electrode. We suggest that the ITO electrode is an optimum surface electrode for the realization of nc-Si based EL device with the high brightness.

Topics: Color; Crystallization; Electric Impedance; Electrochemistry; Electrodes; Glass; Gold; Indium; Luminescence; Luminescent Measurements; Nanoparticles; Nanotechnology; Particle Size; Photochemistry; Silicon; Spectrophotometry, Ultraviolet; Surface Properties; Temperature; Tin Compounds

The use of an optically thin indium-tin-oxide (ITO) electrode is presented for an optoelectric biosensor simultaneously recording optical images and microimpedance to examine time-dependent cellular growth. The transmittance of a 100 nm thick ITO electrode layer is approximately the same as the transmittance of a clean glass substrate, whereas the industry-standard Au(47.5 nm)/Ti(2.5 nm) electrode layer drops the transmittance to less than 10% of that of the glass substrate. The simultaneous optoelectric measurements permit determining the correlation of the cell-covered area increase with the microimpedance increase, and the example results obtained for live porcine pulmonary artery endothelial cells delineate the quantitative and comprehensive nature of cellular attachment and spreading to the substrate, which has not been clearly perceived before.

Topics: Animals; Biosensing Techniques; Cell Adhesion; Electrochemistry; Electrodes; Equipment Design; Indium; Models, Statistical; Nanoparticles; Optics and Photonics; Silicon; Tin Compounds

We propose an optical thin-film characterization technique, differential optical sectioning interference microscopy (DOSIM), for simultaneously measuring the refractive indices and thicknesses of transparent thin films with submicrometer lateral resolution. DOSIM obtains the depth and optical phase information of a thin film by using a dual-scan concept in differential optical sectioning microscopy combined with the Fabry-Perot interferometric effect and allows the solution of refractive index and thickness without the 2pi phase-wrapping ambiguity. Because DOSIM uses a microscope objective as the probe, its lateral resolution achieves the diffraction limit. As a demonstration, we measure the refractive indices and thicknesses of SiO2 thin films grown on Si substrate and indium-tin-oxide thin films grown on a glass substrate. We also compare the measurement results of DOSIM with those of a conventional ellipsometer and an atomic force microscope.

Topics: Calibration; Equipment Design; Indium; Interferometry; Microscopy; Microscopy, Atomic Force; Microscopy, Confocal; Microscopy, Interference; Models, Statistical; Optics and Photonics; Refractometry; Regression Analysis; Silicon; Tin Compounds

Single crystalline SnO(2) nano-needles with length up to 6-7 microm and diameter less than 300 nm are synthesized on an Au-coating porous silicon substrate from SnH(4) source via a glow discharge process.

Topics: Gold; Microscopy, Electron, Scanning; Nanotubes; Silicon; Tin Compounds

Highly polished enamel surfaces are recommended for axial tooth surfaces that will serve as guiding planes and be contacted by component parts of a removable partial denture. There is little evidence to support the assumption that this tooth modification will provide accurate adaptation of the framework and prevent build-up of plaque.. The aim of this investigation was to evaluate the surface roughness of the tooth enamel, prepared to serve as guiding planes, with different polishing systems.. Four different methods (designated A, B, C, and D) for finishing and polishing the prepared enamel surfaces of 20 freshly extracted third molar teeth were studied. Each method involved 3, 4, or 5 different steps. The roughness of each specimen was measured at the start of each method before recontouring, after recontouring, and after each step of the 4 finishing and polishing procedures. The 4 experimental finishing methods were applied after recontouring the axial surfaces (buccal, lingual, and proximal) of each tooth. Thus the 20 teeth (60 surfaces) were finished and polished by use of 1 of the experimental methods. Surface roughness was measured with a profilometer (microm); the readings of the unpolished enamel surfaces were recorded as control measurements. Results were statistically analyzed with one-way analysis of variance followed by Tukey's test at the 95% level of confidence.. The highest roughness mean values (14.41 microm to 16.44 microm) were found when the diamond bur was used at a high speed for tooth preparation. A significant decrease in roughness values was observed with the diamond bur at a low speed (P<.05). Analysis of the roughness values revealed that all polishing methods produced surface roughness similar to that of the corresponding control teeth.. Within the limitations of this study, all finishing procedures tested effectively promoted an enamel surface similar to the original unpolished enamel.

Topics: Analysis of Variance; Dental Abutments; Dental Enamel; Dental Instruments; Denture, Partial, Fixed; Diamond; Humans; Molar; Random Allocation; Silicates; Silicon; Statistics, Nonparametric; Surface Properties; Tin Compounds; Tooth Preparation, Prosthodontic; Tungsten Compounds

Topics: Electron Probe Microanalysis; Indium; Microscopy, Electron, Scanning; Silicon; Silicon Compounds; Tin; Tin Compounds